An introduction deals with the national deinstitutionalization strategy for status offenders (DSO), the scope of the ISOS, and the nature of the evaluation and related research. The report then provides an overview of characteristics of youths in the programs and focuses on the services provided to youths in the Alternatives to Detention, Service Demonstration, and Comparison Service Demonstration programs of ISOS. It discusses the differential outcomes for youths in the Alternatives and Secure Detention groups, in the Service Demonstration and Comparison Service Demonstration groups, and in the Alternatives and Service Demonstration groups. The effectiveness of ISOS in terms of these youths' subsequent contacts with the justice system, self-reported defiant acts, and progress toward social adjustment is weighed. Sources of data include offender records, standardized self-report measures, and interviews. The report then establishes the relation of services and the communty ties of organizations to outcome. The types of offenders in the various evaluated groups are examined, and data are provided on the changing detention rates and the changing characteristics of detained status offenders. Findings show that the project was established in those countries with the most need. In addition, each component of the program provided different services according to cultural and other factors and not based on any selection criteria, and the project's components did not differ in terms of effects when appropriate control measures were taken. Patterns of change among the youths serviced were similar, although each of the evaluated groups was somewhat different initially. Detention decreased sharply in three of the four counties studied during the first program year; the most significant decrease directly attributed to the effects of ISOS was in Cook County. The findings clearly indicate that deterrence is not more effective than treatment in reducing recidivism by status offenders. There is evidence that intervention -- whether detention or community-based programming -- may have a moderate suppression effect on subsequent contacts by youths with the justice system. The effect is primarily for status offenses. Tables, graphs, and footnotes are included. Supplementary tables are appended.